semi implemented and features implemented save checkpoint

docs/features/unchecked/web/frontend-plugin-system.md

@@ -0,0 +1,43 @@
+# Frontend Plugin System (Discovery, Sandbox, Extension Slots)
+
+## Module
+Web
+
+## Status
+IMPLEMENTED
+
+## Description
+Frontend plugin architecture with plugin discovery service, dynamic module loader, sandboxed execution, a registry for managing plugin lifecycle, tenant-scoped plugin configuration, navigation integration for plugin-contributed menu items, and an extension slot component allowing plugins to inject UI at designated extension points.
+
+## Implementation Details
+- **Feature directory**: `src/Web/StellaOps.Web/src/app/core/plugins/`
+- **Components**:
+  - `extension-slot` (`src/Web/StellaOps.Web/src/app/core/plugins/extension-slots/extension-slot.component.ts`)
+- **Services**:
+  - `plugin-discovery` (`src/Web/StellaOps.Web/src/app/core/plugins/discovery/plugin-discovery.service.ts`)
+  - `extension-slot` (`src/Web/StellaOps.Web/src/app/core/plugins/extension-slots/extension-slot.service.ts`)
+  - `plugin-loader` (`src/Web/StellaOps.Web/src/app/core/plugins/loader/plugin-loader.service.ts`)
+  - `plugin-manifest-loader` (`src/Web/StellaOps.Web/src/app/core/plugins/loader/plugin-manifest-loader.service.ts`)
+  - `navigation-plugin` (`src/Web/StellaOps.Web/src/app/core/plugins/navigation/navigation-plugin.service.ts`)
+  - `plugin-registry` (`src/Web/StellaOps.Web/src/app/core/plugins/registry/plugin-registry.service.ts`)
+  - `plugin-sandbox` (`src/Web/StellaOps.Web/src/app/core/plugins/sandbox/plugin-sandbox.service.ts`)
+  - `tenant-plugin-config` (`src/Web/StellaOps.Web/src/app/core/plugins/tenant/tenant-plugin-config.service.ts`)
+- **Models**:
+  - `src/Web/StellaOps.Web/src/app/core/plugins/models/extension-slot.model.ts`
+  - `src/Web/StellaOps.Web/src/app/core/plugins/models/plugin-lifecycle.model.ts`
+  - `src/Web/StellaOps.Web/src/app/core/plugins/models/plugin-manifest.model.ts`
+- **Source**: Feature matrix scan
+
+## E2E Test Plan
+- **Setup**:
+  - [ ] Log in with a user that has appropriate permissions
+  - [ ] Navigate to the relevant page/section where this feature appears
+  - [ ] Ensure test data exists (scanned artifacts, SBOM data, or seed data as needed)
+- **Core verification**:
+  - [ ] Verify the component renders correctly with sample data
+  - [ ] Verify interactive elements respond to user input
+  - [ ] Verify data is fetched and displayed from the correct API endpoints
+- **Edge cases**:
+  - [ ] Verify graceful handling when backend API is unavailable (error state)
+  - [ ] Verify responsive layout at different viewport sizes
+  - [ ] Verify accessibility (keyboard navigation, screen reader labels, ARIA attributes)